Universal joint



Dec. 13, 1938. L. 1.. MALLARD UNIVERSAL JOINT Filed Jan. 18, 1937 w w g m M 2 Q; 5/ W2 13 n WW5 a w W f 1 m 5 6 6 2 W fin w-\\\\y .,/////Z w xo Patented Dec. 13, 1938 UNITED STATES PATENT OFFICE 19 Claims.

This invention relates to universal joints, specifically of the ball and socket type and features improved means for transmitting motion between the elements of the joint while permitting them 5 to assume different relative positions with respect to each other.

An object of the invention is to provide a unispherical elements as the motion transmitting motion between its elements are adapted to. withstand relatively hard usage without the wear and breakage which occurs through the use of spherical elements at the motion transmitting means in known forms of universal joints.

A further object is to provide a device of the character referred to wherein the motion transmitting devices normally present greater areas of c'ontactagainst the walls of the grooves in the adjacent faces of the ball and socket than with known structures, thus materially reducing the wearing of the parts.

A further object is to provide a device of this character having means for minimizing backlash between the coupled joint elements, thus further reducing the wearing of the parts.

A further object is to provide resilient means operating to take up play between the parts in the direction of their normal rotation, thus minimizing backlash and greatly lengthening the usefull life of the device.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the drawing I have shown one embodiment of the invention. In this showing- Figure 1 is a side elevation,

Figure 2 is a central axial sectional view with the coupled shafts shown. in axial alignment, parts being shown in elevation,

Figure 3 is a section on line 3 -3 of Figure 2, and,

Figure 4 is a detail perspective view of one of the motion transmitting elements.

Referring to Figures 1 and 2, the numerals l and II indicate a pair of coupled shaft sections, of which the shaft I0 may be the drive shaft and the'shaft H the driven'shaft. A socket |2 forming one of the joint elements is adapted to rotate with the shaft II and is formed of sections l3 and I4 which are rigidly secured to each other by means of bolts I5 circumferentially spaced from each other and arranged parallel to the axis of the shaft The'socket section |4 is provided with an axial projection l6, splined on the shaft II as at H. The socket I2 is provided with an internal spherical surface l8, and a plurality of circumferentially spaced grooves l9 are formed within'the socket l2, each of these grooves lying in a plane coincident with the axis of the shaft A ball 20 forming the coacting element of the joint is adapted to rotate with the shaft l0, and is provided with an axially extending sleeve 2| keyed or splined as at 22 on'the'shaft flll. The ball 2|lhas a spherical outer surface adapted to fit within the socket |2, as will be apparent. A plurality of circumferentiallyspaced grooves 23 are formed in the ball 20, the grooves 23 corresponding in number and arrangement with the grooves I9 at each line in a plane coincident with the axis of the shaft l0. 7

The ball 20 is provided with an axial recess 24 and the inner end of this recess communicates with an axial opening 25 of smaller diameter. A screw 26 extends through the opening 25 and is threaded in the adjacent end of the shaft III, the head of the screw being arranged in the inner end of the recess 24. It-will be apparent that the screw 26 positively secures the ball 20 against axial movement with respect to the shaft Ill.

The left hand end of the recess 24, as viewed in Figure 2, is internally threaded as at 21 for the reception of a plug 28, the inner end of which is adapted to seat against the head of the screw 26. The free end of the plug 28 is axially recess'ed as at 29 to receive a thrust ball 30 which .engages against the spherical surface |8 of the socket l2.

A motion transmitting device 3| is adapted to be arranged in each corresponding pair of grooves l9 and 23 with a slight clearance between each device and its associated grooves. Each device 3| is provided with a peripheral portion 32 which is substantially semi-circular in cross-section, each groove I9 and 23 having its innermost portion similarly shaped. Considered in planes containing the axis of rotation of the shafts the devices 3| are circular in cross section as shown in side elevation in Fig. 2. Considered in planes at right angles to these axes, the peripheral outlines of the devices are cycloidal exceptthat the crown portions at opposite sides of each device 3| are substantially flat as at.33, as clearly shown in Figure 3.

The sleeve 2| is preferably surrounded by a torsion spring 34 having one end 35 secured by a screw 36 or other fastening element to the socket member l3. The other end 31 of the spring is secured by a screw or the like 38 to the sleeve 2|.

The operation of the device is as follows:

Itwill be apparent that rotation of .the shaft H! in either direction transmits corresponding roassets the shaft u, the motion transmitting tions of the Shafts ill and ii.

devices 3| serving as a positive driving connection between the socket i2 and ball 20. In prior constructions of this general character it has been the common practice to employ spherical elements in place of the devices 3i, but the use of spherical elements is disadvantageous for the reason that each spherical element engages at a single point with the ball and with the socket, thus resulting in unduly rapid wear of the ball and sockets; Moreovensuch singlepoints of contact, "particularly after substantial wear has 1 taken place and backlash has developed are disadvantageous for the reason that the taking up of play under heavy torque conditions subjects the spherical elements to heavy loads at the single points referred to. Such subjection of the balls to heavy thrusts often results in the fractureof the balls.

With the present construction, the use of the devices 3i materially increases the areas of contact between the devices 3i and the grooves i9 23, thus resulting in a greatly retarded wearof the parts.v Moreover, the motion transmitting devices 'are not subjected to heavy thrusts ;at restricted points, and accordingly these elefments; are adapted to withstandsudden heavy loads without beingbroken or fractured.

The ball 12 is formed of separate sections to facilitatethe introduction of the devices 3|, and also to permit the socket to extend on opposite sides of a plane, through the center of the ball '20 at, right angles'tc the axis of the shaft Ill.

As previously stated, the axialprojection it is splined on the shaft Ii as at H, and accordingly the .socket lf isfree for axial movement with the 'ballT2iL-to compensate for relative axial movement of the shafts ill and H under varying driving conditions. For example, if the present device is employed in connection with the propeller shaft of 8,.11101501' vehicle, any increase in the angularity betweentheshaftsi0 and ii results inan elongation of the :propelier shaft, which is compensated for-by free sliding movement of the projection I61on' theshaftnli. .The shafts i0 and il, of course, are adapted to move to relative angular. positions bythe turning of the ball 20in the socket if, the devices 3i preventing relative "rotation between these elements, and thus providing positive driving connections between the parts. The ball acts as an effective thrust-bearing between the ball 20 and socket l2, -as w ill1be apparent, and this ball is arranged in, th e, socket 29 of the plug 28, which elementpositively prevents displacement of the screw. 26..

, Inany-device of the present character, certain limited play exists between the parts, and such play increases very, slowly in the present device due to the characteristics of the devices 3l,- as

previously described. The spring 34 provides means in addition to the particular characteristics af the-devices II for minimizing the wearing of the parts incident to sudden reverse rota- In any installation} for example in a motor vehicle propeller shaft, the shafts I0 and II rotate in the same direction during the greater portion of the periods of operation 'of the apparatus. The torsion' spring 34 tends to, rotate the shafts l0 and H with respect to each other, this rotation, of course, being prevened by the elementsfi. The spring, however, takes up what minor play exists between the parts, and the spring is wound faces of said ball and to tend to rotate the shaft in in the direction in which it is commonly driven.

Under normal driving conditions, therefore, play is prevented from developing between the devices 3i and their respective grooves, and the sudden application of power to the shaft II or torque reaction on the shaft ii is taken up without lost motion, thus greatly minimizing the wearing of the parts, It will beapparent that the spring 34 is not essential to the operation of the universal Joint, but its use is advantageous in connection with the universal Joint itself since it improves the wearing characteristics very materially, and assists in maintaining perfectly quiet operation of the universal joint.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

I claim:

l. A universal joint comprising a socket, a ball arranged in said socket, the opposing faces of said ball and socket having grooves lying in planes coincident with the axes of the socket and ball, and a motion transmitting device arranged in each corresponding pair of grooves, each such device being disk-like in formation, and each having its diameter substantially in a plane passing through the axes of the shafts when the latter are aligned.

2. A universal joint comprising a shaft having a socket thereon, a second shaft having a ball thereon arranged in said socket, the contacting faces of said ball and socket having corresponding grooves lying in planes coincident with the axes of the respective shafts, a non-spherical motion transmitting device arranged in each corresponding pair of grooves, each of relatively flat opposite faces, wise in a plane including the one of the shafts.

3. A universal joint comprising a shaft having a socket thereon, a second shaft having a ball thereon arranged in said socket, the contacting socket having correspondand extending flataxis of rotation of ing grooves lying in axes of the respective shafts, and a motion transmitting device arranged in each corresponding pair of grooves, each such device being disk-like in formation and having its peripheral portion of curved cross-section merging into relatively flat opposite faces, and each having its diameter substantially in a plane passing through the axes of the shafts when the latter are aligned.

4. A universal Joint comprising a shaft having a socket thereon, a seconc'lshaft having a ball thereon arranged in said faces of said ball and said socket having grooves concentric. with the, center of said ball and arranged in corresponding pairs, the grooves of said socket and said ball lying in. planes coincident respectively with the axes of said first and second named shafts, the bottoms of said recesses being curved in cross-section, and a motion transmitting device arranged in each corresponding pair of grooves, each such device being disk-like in formation and having its peripheral portion in cross-section corresponding generally to the crossseotion of the bottoms of said grooves and merging into relatively flat opposite faces.

5. A universal joint comprising a shaft having a socket thereon, a second shaft having aball such devices having planes coincident with the socket, the contactingthereon arranged in said socket, the contacting faces of said socket and said ball having grooves concentric with the center, of said ball and lying in planes coincident with the respective axes of said first and second name shafts, a motion transmitting device arranged in each groove of said socket and the corresponding socket in said ball and spring means tending to impart relative rotation to said shafts.

6. A universal joint comprising a shaft having a socket thereon, a second shaft having a ball thereon arranged in said socket, the contacting faces of said socket and said ball having grooves concentric with the center of said ball and lying in planes coincident with the respective axes of said first and second named shafts, a motion transmitting device arranged in each groove of said socket and the corresponding groove in said ball, and a coiled torsion spring surrounding the axis of one of said shafts and tending to impart relative rotation to said shafts. I

7. A universal joint comprising a shaft having a socket thereon, a second shaft having a ball thereon arranged in said socket, the contacting faces of said ball and socket having corresponding grooves lying-in planes coincident with the axes of the respective shafts, a motion transmitting device arranged in each corresponding pair of grooves, each of such devicesbeing of greater diameter than thickness, and each having its diameter substantially in a plane passing through the axes of the shafts when the latter are aligned, and spring means constantly tending to relatively rotate said shafts to maintain the devices in snug engagement with their respective grooves.

8. A universal joint comprising a shaft having a socket thereon, a second shaft having a ball .thereon arranged in said socket, the contacting faces of said ball and socket having corresponding grooves lying in planes coincident with the axes of the respective shafts, a motion transmittlng device arranged in each corresponding pair of grooves, each such device being disk-like in formation and having its peripheral portion substantially of semicircular cross-section, and each having its diameter substantially in a plane passing through the axes of the shafts when the latter are aligned, and a coiled torsion spring surrounding the axis of one of said shafts and constantly tending to relatively rotate said shafts. 9. A universal joint comprising a pair of shafts, a ball fixed on one shaft, a socket receiving said ball and splined on the other shaft, said socket extending on opposite sides of a plane passing through the center of said ball at right angles to the axis of said first named shaft, the contacting faces of said ball and said socket having grooves concentric with the center of said ball and lying in planes coincident respectively with the axes 'of said first and second named shafts, and a motion transmitting device arranged in each groove of said ball and in the corresponding groove of said socket, each motion transmitting device being of disk-like formation and having itsperipheral portion rounding into substantially flat opposite faces, and each having its: diameter substantially in a plane passing through the axes of the shafts whenthe latter are aligned. t

10. A universal joint comprising-p, shaft, a

'ball having a sleeve extension surrounding the end of said shaft andflxed against rotation-with respect thereto, said ball having an axial recess, a screw having its head arranged in said extending on opposite sides of a plane through the center or said ball at right angles to the of said shaft, a plug in said a thrust.

ments, means connecting said elements in inter driving relation and for universal movement with respect to each other, and spring means con stantl'y' tending to rotate said elements with respect to each other. I

12. A universal joint comprising a pair of coacting members, motion transmitting means connecting said members for simultaneous rotation and for universal movement with respect to each other, and a torsion spring constantly tending to rotate said members with respect to each other to take up back lash in all relative positions of the members. i

13. A universal joint comprising a pair of shafts, a ball carried by one shaft, a socket carried by the other shaft and extending on opposite sides of a plane passing through the center of said ball at right angles to the axis of the first named shaft, the contacting faces of said ball and said socket having grooves concentric with the center of the ball and lying in planes coincident respectively with the axes of said first and secohd named shafts, a motion transmitting device arranged in each groove of said ball and the corresponding groove of said socket, said ball being provided with an axial recessmeans for securing said ball to said first named shalt including a head lying in said recess, a plug mounted in said recess and engaging said head, and a thrust ball carried by Said plug and (2118i? ing said socket. I

14. A universal joint comprising two elements. one intruded into the other, the opposing races of the elements each rovided with a recess, one

of the recesses forming a groove extending in a plane containing the axis of rotation of the ciated element, and a motion transmitting device arranged in both of said recesses, saiddevice be ing approximately of disc-like form with its maxi mum diameter in a plane passing through the axis of rotation of one of the elementsand with its minimum diameter at right angles to its maximum diameter, v

15. A universal joint comprising two elements having a limited freedom of relative atticiiliiitii lhi and meansreacting between the elements and tending to cause one to bear rotatively on the other to take up backdash.

16. In a universal joint, the combination ottwo elements operatively connected to drive one from the other indifferent angiilar positions of their axis of rotation,- and a tension spring onnecting the elements in all or said an ular positions and reacting between the elements rotati-vely in one direction to maintain thepressure from one els ment on to; the other in all relative thereon g v 17. A universal joint comprising two elementsmounted for relative articulation ahoiita point;-

recess and threaded in -the adjacent end of said ,said elements provided with registering recesses shaft, a socket receiving said ball, said socket and a driving connection betweenthe elements '1] bination of a 'bairlo'i' shafts each adapted to roits ow'n axis and adapted to be rela- "contained partly in one recess and partly in its companion recess,one of said recesses forming a groove infa plane containing -.said point and said driving c'onection presenting its greatest area ,fj'ot contact" surface across its line or transmitted E thrust Iandjc'apable ott rev'olving about said line 'ji-I8QIn1a nni'ver'sal joint the combination of a balliiilfovided'with an axially extending bore "having an enlarged outer endand a reduced portion iorm'i'ng a shoulder, a mounting screw having its shank extending through thereduced portion and 'it's' head'i'n the enlarged end engaging said shouldeifa plug fitting in said enlarged end and engaging the screw to hold the same in place. 19. In a device otfthe-class described, the comrelative axial movement of the shafts under vary- 10 ing driving conditions and a torsion spring reacting between the elements of the joint'in a direction tending to move said last named coacting element axially along its associated shaft and away from the shaft to which the first named 15 element of the joint is fixed.

LOGAN L. MALLARD. 

